This application is based on Japanese Patent Application No. Hei 11-348607 filed in Japan on Dec. 8, 1999, the entire content of which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to an image forming apparatus having a copy mode and a printer mode.
2. Description of the Related Art
An image forming apparatus such as a digital copier reads an original to obtain image data, performs various processings on the obtained image data to convert it into print data, and prints the image of the original onto a sheet based on the print data. This operation is called a copy mode.
Some image forming apparatuses have a printer mode as well as the copy mode. In the printer mode, data transmitted from an external apparatus such as a personal computer is input, and an image is printed onto a sheet based on the input data. Image forming apparatuses having the printer mode have an external input interface for inputting data from external apparatuses.
In recent years, it has been required to effectively use memory and hardware resources in image forming apparatuses. Some image forming apparatuses have a panel display processing section for displaying images in a panel display section. Such image forming apparatuses require a VRAM for storing images. Image forming apparatuses having the printer mode require a buffer memory for temporarily storing data from an external apparatus which data is input through the external input interface.
An object of the present invention is to provide an improved image forming apparatus that solves the above-mentioned problems.
Another object of the present invention is to provide an image forming apparatus in which reduction in circuit scale can be realized by effectively using memory and hardware resources.
These objects are achieved by providing an image forming apparatus capable of operating selectively between in the two operation modes, the copy mode and the printer mode, and comprising:
a plurality of VRAMs for storing image data;
a VRAM control circuit for controlling data storage and reading into and from the VRAMs;
a controller for controlling an operation of the VRAM control circuit;
a display for displaying an image based on image data transmitted from the VRAM control circuit; and
an interface for inputting data transmitted from an external apparatus,
wherein the VRAM control circuit has a device in which wiring of a gate array is rearrangeable based on supplied structure information, and
the controller rearranges the wiring of the gate array of the device in the VRAM control circuit according to the operation mode, thereby switching at least one of the VRAMs so as to act as a memory for storing image data for displaying an image on the display or as a buffer for temporarily storing data input through the interface.
In the image forming apparatus, in the copy mode, the controller may rearrange the wiring of the gate array of the device in the VRAM control circuit so that all the VRAMs act as memories for storing image data for displaying an image on the display.
Moreover, in the image forming apparatus, in the printer mode, the controller may rearrange the wiring of the gate array of the device in the VRAM control circuit so that at least one of the VRAMs acts as a buffer for temporarily storing data input through the interface.